1. Field of the Invention
The present invention relates to an optical disc cartridge receiving an optical disc, and in particular to a structure of a disc cartridge from which a disc can be smoothly taken out and which prevents the disc from being damaged, by setting the height of a rib which is positioned at an inner surface of the disc cartridge where a disc holder guiding insertion and removal of the disc is disposed, and which is contacted with a non-recording region of the disc.
2. Description of the Background Art
In general, optical discs are divided into reproducible(that is, read-only) discs such as a CD-ROM and a DVD-ROM, and writable discs such as a write once read many WORM type, a rewritable type and a RAM type, in accordance with the number of time the disc can be written to.
As the writable disc is of high density, its information recording side may be easily contaminated with dust or fingerprints, or scratched.
Accordingly, the writable disc is generally received in a cartridge in order not to be contaminated or damaged.
A conventional disc cartridge will now be described with reference to FIGS. 1 and 2.
FIG. 1 is a plan view illustrating a general disc cartridge, and FIG. 2 is a cross-sectional view taken along line II-II′ in FIG. 1.
As shown in FIGS. 1 and 2, in the general disc cartridge at upper and lower inner surfaces of a casing 12 receiving a disc 11, ribs 13 are formed facing each other.
The ribs 13 contact with a non-writable clamping region at an inner circumferential portion of the disc 11, and keep the writable portion of the disc 11 separated from the inner surface of the casing 12 by a predetermined spacing, thereby preventing the recording side of the disc 11 from being damaged due to contact with the inner surface of the casing 12.
Pursuant to the standard for the digital video disc (DVD), the height of the ribs 13 in the disc cartridge 10 is not set. However, the height of the ribs 13 is defined when a thickness T between an outer surface of the casing 12 and an inner surface thereof and a height H between the outer surface of the casing 12 and the rib 13 is set.
Here, the thickness T has a maximum value of 2.2 mm, and the height H has a maximum value of 2.5 mm. Accordingly, the manufacturing companies can freely set the height of the rib 13 so long as the conditions of T and H are satisfied.
It is possible to remove the ribs 13 where the disc 11 is mounted in a drive. However, as described above, the recording side of the disc 11 may be damaged due to contact with the inner surface of the casing 12, and thus the ribs 13 having a predetermined height need to be formed in the casing 12.
On the other hand, there has been suggested a disc cartridge from which the disc can be taken out when the user so desires. In general, when the disc is taken out, the recording side of the disc may be damaged due to carelessness of the user, or contaminated with fingerprints. Accordingly, there is provided a disc cartridge including a disc holder for opening/closing a disc receiving groove in the casing.
For example, a disc cartridge disclosed in Korean Patent Application No. 98-28766 applied for registration by the applicant concerned and also filed in U.S. as application Ser. No. 09-347388 on Jul. 6, 1999 will now be explained with reference to FIG. 3.
FIG. 3 is an exploded plan view illustrating a disc cartridge having a tension-arm disc holder.
As shown therein, a disc holder 30 is provided with tension arms 31, 31′ formed in a single body (hereinafter, referred to as ‘tension arm-disc holder’).
In case the disc 11 is received in a casing 20 or taken out from the casing 20, although the user does not directly touch the disc 11, the tension arm disc holder 30 holds the disc 11 by an elastic force of the tension arms 31, 31′.
When the disc 11 is guided into the disc cartridge, the tension arms 31, 31′ of the tension arm disc holder 30 contact with guide ribs 21, 21′ formed at a rear portion of the casing 20, whereby the tension arms 31, 31′ are spread apart and thereby the disc 11 is released from the tension arms 31, 31′.
The tension arm disc holder 30 holds an outer circumferential surface of the disc 11 by the elastic force, thus minimizing contamination by fingerprints or the likes.
However, in the earlier proposed disc cartridge employing a tension arm disc holder, the height of the rib protruded in the disc cartridge is not specifically regulated, and thus the disc 11 and the tension arms 31, 31′ may interfere with each other in the disc cartridge where the tension arm disc holder 30 is disposed.
FIG. 4 is a cross-sectional view illustrating a disc cartridge provided with the tension arm disc holder 30 for showing the interference between the disc 11 and the tension arms 31, 31′. The tension arm 31, 31′ are contacted with the guide ribs 21, 21′, thereby being separated from the disc 11.
Normally, the disc 11 is positioned in order for its outer circumferential surface to face a receiving groove 40 formed between flanges 32, 32′ of the tension arms 31, 31′. In case the outer circumferential surface of the disc 11 is downwardly deflected due to the weight of the disc 11, the disc 11 may interfere with the lower flange 32 of the flanges 32, 32′ guiding the disc 11 into the receiving groove 40.
In this case, the tension arm-disc holder 30 cannot be taken out due to interference between the casing 20, the disc 11 and the tension arms 31, 31′. Even if the tension arm-disc holder 30 is externally taken out, the disc recording side may be scratched or contaminated due to the interference between the flanges 32, 32′ and the disc 11.
In addition, in a recording or reproducing mode, the disc 11 cannot be normally rotated due to the interference between the disc 11 and the flanges 32, 32′, and thus it is impossible to perform a recording/reproducing operation. Moreover, the disc may be seriously damaged.